Supervisory system



Och 1942- c. E. STEWART SUPERVISORY SYSTEM Filed Feb. l, 1941 2Sheets-Sheet 1 Inventor Glade E. Stewart,

b8 His Attorneg.

Oct. 13, 1942. c STEWART SUPERVISORY SYSTEM Filed Feb. 1, 1941 ZSheetS-Sheet 2 Inventor. Clyde E. Stewart, b9 flaw 1y 5. 1 444 4 1 HisAttorney.

Patented Oct. 13, 1942 SUPERVISORY SYSTEM Clyde E. Stewart, Upper Darby,Pa., assignor to General Electric Company, a. corporation of New YorkApplication February 1, 1941, Serial No. 377,033

32 Claims.

My invention relates to supervisory systems and particularly tosupervisory systems in which means are provided whereby a currentimpulse of a character depending upon the position of a movableapparatus unit at a remote station is transmitted to a dispatchersoflice after a connection has been established between an apparatus unitand the corresponding signalling means at the dispatche'rs oflice. Whenthe apparatus unit is a device which is adapted to be restored quicklyto its normal position, when it is moved out of that position, such, forexample, as an automatically reclosed circuit breaker, there i thepossibility that the apparatus unit may be restored to its normalposition beforethe supervisory apparatus can function to transmit acurrent impulse corresponding to the out-of-normal position of theoperated unit. Consequently, when an indicating impulse is finallytransmitted, it is of the character corresponding to the normal positionof theunit and, therefore, no change in the signalling means at thedispatchers office is effected to inform the dispatcher that theapparatus unit has changed its position.

One object of my invention is to provide in a supervisory system animproved arrangement of apparatus whereby any change of an apparatusunit at the remote station from its normal position is permanentlyindicated at the dispatchers office until acknowledged by the dispatchernotwithstanding the fact that the apparatus unit may be restored to itsnormal position so quickly,

that no indicating impulse corresponding to the unit is transmittedwhile it is out of its normal position.

This application is a continuation-in-part of my copending application,S. N. 265,227, filed March 31, 1939, now abandoned.

My invention will be better understood from the following descriptionwhen taken in connection with the accompanying drawings, Fig. 1 of whichdiagrammatically illustrates a supervisory system of the synchronousselector type embodying my invention, and Fig. 2 of whichdiagrammati-cally illustrates a supervisory system of the code selectortype embodyin my invention, and the scope of my invention will bepointed out in the appended claims.

In Fig. 1 of the accompanying drawings, Lhave shown only as much of acomplete synchronous selector supervisory system of the type disclosedin U. S. Letters Patent 1,945,665, granted Februmy 6, 1934, to theassignee of this application as is necessary for a completeunderstanding of the mote station (RS).

this type are well known in the art. As shown, the supervisory systemincludes three conductors L-l, Ir-2 and L-3 extending between adispatcher's oflice DO and a remote station RS. The line conductorsL-'l, L2 and L-3 are respectively called the common line, the indicatingline, and the synchronizing line. The common line L-| interconnects theneutral terminal n of a battery B at the dispatchers oflice (DO) and theneutral terminal n of a battery B at the re- The indicating line L--2interconnects the movable contact of a bank of contacts 1-81 of a switchI--S at the dispatchers oifice DO and the movable contact of a bank ofcontacts l-SI of a switch |--S' at the remote station RS. Thesynchronizing line L-3 interconnects the movable contact of a bank ofcontacts l-SS of the switch l-S and the movable contact ot a bank ofcontacts I--SS' of the switch I S' at the remote station. The switchl-S, as shown, is a selector switch of the well known rotary typecomprising several banks of stationary contacts and indicated here as: ISN, l-- SS, ISI, l--ST, l-SC, and l-SM, each of which has a movablecontact mounted on a common rotatable member which is arranged to berotated by a motor magnet 'l-SM in a manner well known in the art eachtime themagnet l-SM i deenergized. The switch l-S' is a similar switchcomprising five banks of stationary contacts: l--S'N', l-S'S', IS'I',I-ST and I-SC, and a motor magnet IS'M' for simultaneously rotating thecooperating movable contacts for the five banks of stationary contacts.

In actual practice the switches I-S and 1-45 usually have 25 positions,but in order to simplify the disclosure they are shown as having only 6positions.

At the remote station RS there are a number of apparatus units, thepositions of which are to be indicated at the dispatchers ofiice DO.Each of these apparatus units is allotted to different correspondingpredetermined positions of the switches 1-8 and l-S', but in order tosimplify the disclosure, only the apparatus unit A'U'-3, associated withthe third ofi-normal positions of the switches IS and l-S', is shown.This apparatus unit AU'--3 is shown as an automatically reclosed circuitbreaker having aclosing coil 2, a trip coil 3, and a latch 4 for holdingthe circuit breaker in its closed position. The trip coil 3 is connectedin series relation with an electric circuit 5 containing the circuitbreaker AU'-3 so that, when the current in the circuit present inventionbecause supervisory systems of 5 exceeds a predetermined value, thelatch 4 is released to allow the circuit breaker to open. As soon as thecircuit breaker A'U'3"has opened so that its auxiliary contacts 6 arclosed and the latch 4 is restored to its latching position, a circuitis completed for the closing coil 2 t reclose the circuit breaker if aswitch 1 associated therewith is also closed.

Associated with the apparatus unit AU'-3 at the remote station is anindicating relay I'A'-3 which is normally in its energized position andwhich is arranged to be deenergized in response to any change in theposition of the apparatus until A'U'3 whenever the relay IA'3 isenergized. The normally energized circuit for the relay IA'-3 includesthe contacts I of the relay IA3 and either the contacts II or thecontacts, l8 of the circuit breaker I depending upon the position of thecircuit breaker A'U'3 when the last indicating impulse correspondingthereto was transmitted to the dispatcher's ofiice.

' At the dispatchers oflice DO there is provided for each apparatus unitan individual set of three signal lamps such as LR3, LG-3 and LW3 forthe apparatus unit A'U'3. When the lamp LR3 is lighted, it indicatesthat the circuit breaker A'U'3 is closed, and when the lamp LG-3 islighted, it indicates that the circuit breaker A'U'3 is open. The lampLW3, when lighted simultaneously with either of the other two lamps,indicates that the position of a two-position disagreement key DK3,which is individual to the circuit breaker A'U'3, does not agree withthe position of the circuit breaker A'U'3 as indicated by the lamps LR.3and LG3. When the lamp LW3 is lighted, it can be extinguished by movingthe associated disagreement key DK3 to its other position.

The lighting of the lamps LR--3, LG3 and LW3 is controlled by atwo-position polarized indicating relay IR,3, which is individual to theapparatus unit A'U'3, and the winding of which is interconnected betweenthe neutral terminal n of the battery B and the third off-normal contactof bank i-SI. Since the third ofi-normal contact of the bank I-S'I isarranged to be connected to the positive terminal of the battery B atthe remote station when the circuit breaker A"U-3 is closed and to thenegative terminal of the battery B when the circuit breaker A'U'3 isopen, it is evident that the direction of the current flow through thewinding of the polarized relay IRr 3 when the circuit of this relay iscompleted over the indicating line L2 in the third off-normal positionof the switches IS and |S' depends upon the position of the apparatusunit AU3 at that time.

Normally the switches IS and l-S' are at rest in the positions in whichthey are shown in the drawings and synchronous operation of theseswitches from these normal positions may be started by eithermomentarily closing a manually operated start switch ST at thedispatchers oflice or by any one of the apparatus units at the remotestation changing its position and thereby effecting the deenergizationof the associated indicating relay. When the start switch ST is closed,it completes through the normal contacts of banks l-SI and l-S'I' andthe indicating conductor L2 an energizing circuit for a start relay A atthe remote station which in turn by closing its contacts I2 completesthrough the normal contact of banks l-S'S and l-SS and the synchronizingline L-3 an energizing circuit for the polarized selector synchronizingrelays S'SR' and SSH. These synchronizing relays effect in a mannerdisclosed in the aforesaid Letters Patent 1,945,665 the synchronousoperation of the motor magnets l-SM and I--SM to move the switches I-Sand |S to their first off-normal positions.

When any one of the apparatus units at the remote station changes itsposition so that the associated indicating relay is deenergized, such asthe indicating relay I'A'3 associated with the apparatus unit A'U'3, anenergizing circuit is completed for a second starting relay AA at theremote station. By closing its contacts l4, which are in parallel withthe contacts l2 of the start relay A, relay A'A' completes theenergizing circuit of the selector synchronizing relays SS'R' and SSR tostart the synchronous operation of the switches 1-8 and i-S'. Afterbeing started, the synchronous operation of the switches I-S and I-S'continues until the switches either are restored to their normalpositions or reach positions in which either the corresponding selectkey at the dispatchers office is out of its normal position or thecorresponding indicating relay at the remote station is deenergized. Forexample, if the select key SK3, which is individual to the apparatusunit A'U'3, is operated, the circuit through the synchronizing line L3is open when the switch l--S reaches its third oil-normal position. Ifthe indicating relay IA3 is deenergized, the circuit through thesynchronizing line L3 is open at the contact l6 of the relay I'A'3 whenthe switch I-S reaches its third ofi-normal position. Therefore both ofthe switches |S and |-S' will stop in their third off-normal positionsif either the select key SK3 is in its operated position or theindicating relay IA'-3 is deenergized. However, if the select key SK-3is in its normal position and the relay I'A'3 is energized when theswitches IS and IS' reach their third off-normal positions, theenergizing circuit for the selector synchronizing relays SSH and S'SR'is immediately completed to effect the movement of both of the switchesto their fourth off-normal positions.

Whenever both of the switches I-S and l--S' are simultaneously in theirthird oil-normal positions, a circuit is completed for the indicatingrelay IR,3 at the dispatchers office through the indicating line L2 andthe resistor l9 to the positive terminal of the battery B throughcontacts ll of apparatus unit A'U'3, if it is closed, or to the negativeterminal of the battery B through the contacts l8 of the apparatus unitA'U'3, if it is open. Therefore, if the apparatus unit A'U--3 is closed,the polarized relay IRr-3 is operated to the position in which it isshown so as to eiTect the lighting of the lamp LR-3, whereas if theapparatus unit A'U'3 is open, the relay IR3 is operated to its otherposition in which it effects the lighting of the lamp LG3. The lamp LW3is lighted in case the position of the disagreement key DK3 does notagree with the position of the apparatus unit A'U'3 as indicated by thelamps LR-3 and LG-3.

Since the apparatus unit A'U-3 may open and reclose before the switchesI--S and l-S can reach their third off-normal positions after the relayIA'3 is deenergized in response to the opening of the apparatus unit, itis evident that, when the indicating impulse corresponding to theapparatus unit is transmitted after such an operation thereof, it willbe of such a character as to effect no change in the lighting of thelamps LRr-3 and LW3 as the lamp LR-3 will continue to indicate that theapparatus unit A'U'3 is in its closed position and thedisagreement keyDK-3 is still in its position corresponding to the closedposition of theassociated apparatus unit. In order that the dispatcher may be. informedof such an automaticoperation of the apparatus unit A'U'-3, I provide inthe embodiment of my invention shown in the drawings an arrangement forflashing one ofthe associated lamps, such as the lamp LW-3, after anysuch.reclosing operation of the apparatus unit AU'--3. This result isaccomplished by providing at the dispatchers oflice, for each apparatusunit at the remote station, an individual relay which is energizedwhenever theswitches l-S and l--S' remain in the positions thereofallotted to the corresponding apparatus unit for a predetermined timewhich is longer than the time they remain in the same position whenthere has been no change in the position of the corresponding apparatusunit since the last indicating impulse thereof was transmitted. For theapparatus unit AU'-3. this relay is H-3, the energizing circuit of whichis arranged to be completed through the contacts 3 of l--SM, 2!! of arelay and the contacts 2| of a time relay D when the switch |S remainsin its third off-normal position for a predetermined length of time. Thecircuit of the time relay D is controlled so that, during thesynchronous operation of the switches l-S and l-S, it cannot pick up andclose its contacts 2|, but whenever the switches remain in any one oftheir offnormal positions for a predetermined time, the relay D operatesto close its contacts 2| and open its contacts 22 in an energizingcircuit for the relay C which is arranged to open its contacts 20 apredetermined time after it is deenergized. Therefore. the originalenergizing circuit of the relay H-3 is completed for only a short periodof time.

whenever the switches |-S and l -S' are stopped in their thirdoiT-normal positions. By closing its contacts 24 the relay H3 completesa locking circuit for itself through contacts 25 of the select key SK-3if it is in its normal position, contacts 26 of the disagreementkeyDK--3 if it is in its position corresponding to the closed position ofthe apparatus unit AU'-3. and contacts 21 of the indicating relay IR-3if it is in its position corresponding to the closed position of theapparatusunit AU'-3. Relav H-3, therefore, is energized in case theswitches l--S and l--S' are stopped in their third offnormal positionsdue to an automatic o ening and reclosing of the apparatus unit A'U'--3before an indicating impulse corresponding to.

the open position of the apparatus unit can be transmitted. If theapparatus unit AU'-3 remains open long enough so that an indicatingimpulse corresponding to the open position of the apparatus unit istransmitted, the indicating relay IR-3 at the dispatchers ofiice isoperated by this indicating impulse so that it occupies its otherposition and thereby opens the locking circuit for the relay H-'-3.Therefore, the relay H--3 becomes deenergized as soon as the relay Copens its contacts 20 after the switches l-S and l--S' have stopped intheir third off-normal positions.

At the remote station a time relay D is provided which is arranged topick up and close its contacts 26 whenever the switch i-S' is stopped inany of its off-normal positions. Therefore. When the switch 'I-S' stopsin its third off normal position due to an automatic operation of theapparatus unit AU'-3, which also effects the deenergization of theasociated relay I'A'3, a circuit is completed for a time relay H'-3.After being energized for a predetermined time, the relay H'3 completesan energizing circuit for the deenergized indicating relay IA3 and alsocompletes a circuit for the synchronizing relays SSR and S'S'R' so thatthe synchronous operation of the switches l-S and I-S' is again startedto restore them to their normal positions.

When the switch l-S is restored to its normal position, a circuit iscompleted through the normal contact of bank |-ST at the dispatchersofiice for a control relay E. If the relay H-3 is energized when therelay E becomes energized, a circuit is completed for a relay F which inturn completes a flashing circuit for the lamp LW--3 through aninterrupter IR so that the lamp LW--3 is intermittently lighted at thesame time the lamp LIL-3 is continuously lighted. This combination oflamps informs the dispatcher that the apparatus unit AU'-3 has openedand automatically reclosed. By moving the disagreement key DK--3 to theposition thereof corresponding to the'open position of the apparatusunit A'U'3, the dispatcher can effect the deenergization of the relayH--3 so as to stop the intermittent lighting of the lamp LW-3 and causeit to be lighted continuously. Then by moving the disagreement key DK-3back to the position thereof corresponding to the closed position of theapparatus unit A'U3, the dispatcher can extinguish the lamp LW-3completely.

The operation of the arrangement shown in the drawings is as follows:

When the switches |S and 1-8 are at rest in their normal positions andthe apparatus unit AU'-3 is closed, the various control devices of thesupervisory equipment occupy the positions in which they are shown inthe drawmgs. circuit for the relay E is completed through the normalcontact of bank l-S'I and an energizing circuit is completed for therelay C through the contacts 22 of the deenergized relay D. A circuit iscompleted for the lamp LR-3 through the contacts 30 of the indicatingrelay IRP-3 so that this lamp is continuously lighted thereby informingthe dispatcher that the apparatus unit A'U-3 at the remote station isclosed. At the l remote station the indicating relay I'A'3 is energizedby a locking circuit which includes the contacts In of the relay I'A'-3and the auxiliary contacts I! of the closed apparatus unit A'U '-3.

It will be assumed first that the start switch ST is closed momentarilyto'complete an energizing circuit for start relay A through the normalcontacts of bank I-SI and l-SI' and the indicating line L-2. By closingits contacts l2, relay A completes through the normal contacts of banksl-SS and |-s's' its the synchronizing line L--3 an energizing circuitfor the synchronizing relays SSH. and S'SR' which effect in a 'wellknown manner the synchronous operation of the switches l-S again reachtheir normal positions in case all of the indicating relays at theremote station are energized and all of the select keys at thedispatchers office are in their normal positions. When the switches I-Sand l-S' reach their third off-norma1 positions, an energizing circuitAt the dispatchers office an energizing and IS' until they.

immediately completed through the contacts l5 of the select key SK-3 atthe dispatchers oflice and the contact I6 of the energized indicatingrelay I'A3 at the remote station so that the switches immediately moveto their fourth ffnormal positions. During the short time that theswitches [-8 and IS' are in their third offnormal positions, anindicating impulse is transmitted over the indicating line L2 to theindicating relay IR3 at the dispatchers oifice through the resistor l9and the contacts I! of the closed apparatus unit AU--3. This indicatingimpulse is of such a character, however, that the relay lR-3 remains inthe position in which it is shown so that the lamp LR3 remainscontinuously lighted.

It will now be assumed that, while the switches I-S and l--S are at restin their normalpositions, the apparatus unit AU'-3 automatically opensso that its contacts I] interrupt the holding circuit for the associatedindicating relay I'A3. By closing its contacts l3, relay I'A3 completesan energizing circuit for the start relay AA' which in turn starts thesynchronous operation of the switches l-'-S and l-S by closing itscontacts I4. Synchronous operation of the switches l--S and IS thencontinues until they reach their third oiT-normal positions where theystop because the synchronizing circuit is open at the contact l6 of thedeenergized indicating relay I'A3.

A circuit is completed for a time relay D at the dispatchers oflice tothe opposite terminals of the battery B through alternate ofi-normalcontacts of the bank l-SC, and a circuit is completed for the time relayD at the remote station to the opposite terminals of the battery Bthrough alternate oil-normal contacts of bank l-SC so that, during thesynchronous operation of the switches IS and IS', the currents throughthe relays D and D' are reversed at such a rate that they cannot pickup.However, when the switches I-S and I-S remain in any off-normal positionfor a predetermined time which is longer than the time they remaintherein during normal synchronous operation, the relays D and D havetime to pick up. Therefore, when the switches IS and l-S' reach theirthird offnormal positions due to the deenergization of the indicatingrelay I'A3, the relays D and D are energized for a suflicient length oftime pick up. By opening its contacts 22, relay D opens the circuit ofrelay C and by closing its contacts 2|, relay D completes an energizingcircuit for relay H--3 through contacts 20 of relay C and the thirdoff-normal contact of bank l-SM. By closing its contacts 24, relay H3completes a locking circuit for itself through contacts 25 of the selectkey SK3, contacts 26 of disagreement key DK3 and contacts 21 of relayIR3.

At the remote station the closing of the contacts 26 of the relay Dcompletes an energizing circuit for the relay H--3 through the thirdoffnormal contact of bank l-ST' and contacts 3| of the deenergizedindicating relay I'A3. After a time interval, relay 1-1-3 closes itscontacts 32 and 33. The closing of the contacts 32 reestablishes thesynchronizing circuit so that the synchronizing relays SSR and S'SR' areagain energized to start the synchronous operation of the switches ISand I'S'. The closing of the contacts 33 of the relay H-3 completes anenergizing circuit for the indicating relay I'A3 through the contacts 26of relay D, the third 01T- normal contact of bank IS'T', and eithercontacts I! or l8 of the apparatus unit A'U'3 depending upon theposition of this unit. By closing its contacts "I, the relay I'A3completes a holding circuit for itself. Since the contacts 33 of relayH'3 reestablish the synchronizing circuit after the switches IS and I-S'have remained in an oif-normal position for a predetermined time due tothe deenergization of the indicating relay associated with theoff-normal position, it will be evident that the relay I-I'3 preventsthe supervisory equipment from becoming stalled in an off-normalposition due to the auxiliary contacts I! or 18 of the correspondingapparatus unit failing to close and complete the energy circuit for theassociated indicating relay.

If the apparatus unit AU3 is still open when the switches IS and |-S'stop in their third ofi-normal positions in response to an automaticopening of the apparatus unit A'U'--3, a circuit is completed forindicating relay IR,--3 through the third off-normal contact of bankl-SI, indicating conductor L-2, third ofi-normal contact of bank l--S'I,resistor 19, contact I8 of the open apparatus unit AU'-'3 to thenegative terminal of battery B. This indicating impulse is of such acharacter that the indicating relay IR3 moves to its other position sothat the contacts 21 and 30 are opened and the contacts 34 are closed.The opening of the contacts 21 interrupts the locking circuit of therelay H3 so that this relay becomes deenergized as soon as the timerelay C opens its contacts 20 in the original energizing circuit forrelay H-3. The opening of the contacts 30 extinguishes the lamp LR-3,and the closing of the contacts 34 completes a circuit for lamp LG-3directly across the terminals of the battery B and a circuit for thelamp LW-3 across the terminals of the battery B through contacts 35 ofrelay 1-1-3 when it is in its deenergized position and contacts 36 ofthe disagreement key DK3. The continuous lighting of the lamps LG--3 andLW3 informs the dispatcher that the apparatus unit A'U-3 has opened andis still in its open position. By moving the disagreement key DK3 to itsother position, the circuit of the lamp LW--3 is opened so that only thelamp LG-3 remains lighted.

It will now be assumed that, after the apparatus unit A'U'-3 opens, itis immediately reclosed andis in its closed position when the switches|S and IS are stopped in their third ofi-normal positions in the mannerabove described. Under these conditions, the indicating circuit for theindicating relay IR3 in the third off-normal positions of the switchesl-S and lS' is connected to the positive terminal of the battery B bythe auxiliary contact I! of the closed apparatus unit AU3. Therefore,when this indicating impulse is transmitted, it does not change theposition of the indicating relay IR3. Consequently, the locking circuitof the relay I-I--3 remains completed when the synchronous operation ofthe switches l-S and l-S is again started by the energization of relayH'3 at the remote station in the manner heretofore described.

As soon as the switches lS and l-S' reach their normal positions and therelay E becomes energized, the closing of its contacts 31 completesthrough contacts 38 of the energized relay H3 an energizing circuit forrelay F. The closing of the contacts 39 of relay F completes a lockingcircuit for the relay F around the contacts 31 of relay E, and theclosing of the contacts 40 of relay F completes a flashing circuit forthe lighted.

In case the dispatcher fails to acknowledge th transmission of anindicating impulse corresponding to the open position of the apparatusunit A'U--3, by moving the disagreement key DK3 to the position thereofcorresponding to the open position of the apparatus unit AU'3, before.it is automatically reclosed and an indicating impulse corresponding tothe closed position is subsequently transmitted, it is evident that thelookin circuit of relay F is completed in response to the transmissionof the indicating impulse corresponding to the closed position of theunit. Therefore, when the switches 1-3 and l-S' return to their normalpositions, the lamp LW3 is intermittently lighted until the dispatcheroperates the disagreement key DK-3 in the manner above described.

In case the dispatcher desires to manually control from the dispatchersoiiice the apparatus unit AU-3, he opens -the select key SK3 beforemomentarily operating the start key ST. Therefore, when the switches l-Sand IS' stop in their third off-normalpositions due to the opening ofthe select key SK--3, the relay H3 becomes deenergized as soon as relayC opens its contacts because the locking circuit of relay H--3 is openat the contacts of select key SK-3. Therefore, there is no intermittentoperation of the lamp LW--3 in response to the manual operation of theapparatus unit A'U-3 by the dispatcher.

In Fig. 2 of the accompanying drawings I have shown my invention inconnection with a code selector supervisory system of the particulartype disclosed in United States Letters Patent 2,205,894, granted June25, 1940, and assigned to the assignee of this application, but it willbe obvious that my invention is not limited to this particular type ofcode selector supervisory system. In order to simplify the disclosure inthe present application, only that portion of the supervisory systemdisclosed in the aforesaid patcut is illustratedin detail in Fig. 2 asis deemed necessary for a complete understanding of the presentinvention.

In Fig. 2 the supervisory system includes two conductors L-l and L-Zextending between a dispatchers offi-ce DO and a remote station RS. Atthe dispatchers oflice a group of control keys and indicating lamps isprovided for each apparatus unit to be selected and controlled at theremote station. Only one such group of keys and lamps is shown in Fig.2, and this includes a two-positionselect key SK-3, which is operated bythe dispatcher when he wants to select the-corresponding apparatus unitAU3 at the remote station for operation and a two-position disagreementkey DK--3 which controls the operation of the corresponding indicatinglamps. The apparatus unit A'U'-3 is shown as an automatic reclosedcircuit breakerwhich is similar in construction and operation to thecircuit breaker A'U--3 shown in Fig. 1.

The illustrated group of lamps includes a red lamp LR-3, which, whenlighted, indicates that the corresponding apparatus unit A'U'--3 is inone position, such as its closed position; a green lamp LG--3, which,when lighted, indicates that the corresponding apparatus unit AU3 is inanother position, such as its open position; and a white lamp LW-3,which, when continuously lighted, indicates that the position of thecorresponding apparatus unit A'U--3 does not correspend with theposition of th associated disagreement key DK-3. Each group of keys andlamps has associated therewith an individual in dicating relay, such asIR-3, which determines by its position whether the associated red orgreen lamp is lighted and which cooperates with the associateddisagreement key DK3 so as to determine whether the associated whitelamp LW--3 is lighted. The position of the indicating relay IR-3 isdetermined by the position of the corresponding apparatus unit A'U'--3at the re-' mote station.

As disclosed in detail in the aforesaid Letters Patent 2,205,894, whenthe dispatcher desires to select the apparatus unit A'U'-3 at the remotestation RS, he operates the corresponding select key SK--3 at thedispatchers ofiice, and this effects the operation of various devices atthe dispatchers office including two finder switches l-F and i2--F whichare operated to positions corresponding to the operated select key SK3.

The positions in which the finder switches l-F and 2F stop determine theselect code. As soon as the finder switches l-F and 2--F stop in thepositions corresponding to the operated select key SK-3, the operationof a code finder l-S is initiated to transmit over the two lineconductors L-l and L-Z the code.of impulses which has been set up by theoperated finder switch I F.

The finder switches IF and 2F and the code sender l--S are shown asbeing selector switches of the well known rotary type comprising aplurality of banks of contacts, each bank having as-- sociated therewitha cooperating wiper and means for simultaneously operating all of thewipers in a step by step movement. Only those banks of contacts areshown in Fig. 2 as are necessary for a clear understanding of thepresent invention. Consequently, I have shown only the banks I-FB of thefinder switch l-F, the banks 2-F3 and 2-F5 of the finder switch 2-F andthe banks l-S4 and l-S5 of the code sender I-S.

At the remote station RS the code of im ulses, which is transmitted overthe line conductors L-l and L-Z, selectively controls a receiver R so asto select the apparatus unit AU-3. At the termination of thetransmission of theselect code, two finder switches l-F' and 2-F' at theremote station are operated to positions corresponding to the apparatusunit selected by the receiver R. As soon as the finder switches l-F and2F, which are similar in construction to the finder switches l-F and 2-Fat the dispatchers o fiice, have reached the positions corresponding tothe selected apparatus unit, a code sender I-S, at the remote station RSand similar in construction to the code sender 'l-S, is started toeffect the transmission to the dispatchers oiiice over theline'conductors Ll and L-2, a check code of current impulses, whichdepends upon the positions of the finder switches I-F' and 2-F'. Thischeck code of impulses is followed by either a positive or a negativeindiwith indicate the position then occupied by the.

selected apparatus unit. Also the necessary circuit connections areestablished at the dispatchers office so that the dispatcher canoperatethe selected apparatus unit as many times as he desires and can releasethe connectionwhenever he so desires.

when the supervisory equipment is at rest and an apparatus unit at theremote station changes its position, the associated indicating relay,such as I'A'-3 associated with the apparatus unit A'U'-3, is deenergizedand causes the finder switches l--F and 2F' to move to the positionsthereof corresponding to the apparatus unit which has changed itsposition. Then the code sender IS" operates to transmit select code ofcurrent impulses corresponding to the apparatus unit which has changedits position. This select code, however, is not immediately followed byan indicating impulse corresponding to the new position of the apparatusunit which has changed its position.

At the dispatchers oflice this select code operates the receiver R so asto select the group of indicating lamps and associated relayscorresponding to the apparatus unit which has changed its position. Atthe termination of the transmission of the select code the two finderswitches IF and 2-F at the dispatchers offlce are operated to thepositions thereof corresponding to the group of indicating lamps andrelays selected by the receiver R. As soon as the finder switches I--Fand 2F have reached the positions corresponding to the selected group ofindicating lamps and relays, the code sender I--S operates to transmitto the remote station RS over the line conductors Ll and L2 a check codeof impulses corresponding to the selected group of indicating lamps andrelays.

At the remote station the check code of impulses selectively controlsthe receiver R. If

the select and check codes agree, the receiver R l effects, after thetermination of the check code, the transmission over the line conductorsL-l and L-2 of an indicating impulse of a polarity corresponding to theposition of the apparatus unit which has changed its position. At thedispatchers ofiice this indicating impulse selectively operates theselected group of lampsso as to indicate the position of the apparatusunit which has changed its position. As soon as the indication impulsehas been transmitted, the selective apparatus automatically resets tonormal.

As disclosed in detail in the aforesaid Letters Patent 2,205,894, thereis provided at the dispatchers oflice (DO) a relay N-3, which isenergized only when the code sender I-S is in its normal position; arelay S-I, which operates after the finder switch l-F has stopped in anyof its normal positions; and a relay -3, which is energized in case thereceiver R receives a code of impulses before the code sender l-S isoperated to transmit a code of impulses, namely, only in case theoperation of the supervisory equipment is initiated in response to oneof the apparatus units at the remote station RS changing its position.

In the arrangement disclosed in the aforesaid patent, it an apparatusunit should move from its normal position to its oil-normal position andthen be restored to its normal position before the supervisory equipmenthas completed the connection to the corresponding indicating means atthe dispatchers oflice, the indicating impulse, which is transmittedafter the connection has been established, will be of the polaritycorresponding to the normal position of the apparatus unit.Consequently, there will be no change in the lighting of thecorresponding red, green or white lamps at the dispatchers oflice.

In order to obtain a permanent indication of such a change in theposition of an apparatus unit, I provide each group of indicating lampsin Fig. 2 with a separate relay, which is arranged to be energized inresponse to the finder switch IF being moved to the position thereofallotted to the associated indicating means as a result of thecorresponding apparatus unit changing its position. This is accomplishedin the embodiment of my invention, shown in Fig. 2, by completing thecircuit of each separate relay, such as relay H3 corresponding to theapparatus unit AU-3, through the contacts 9 of relay 0-3 and contacts eof relay Sl after the finder switch has stopped in the position thereofallotted to apparatus unit AU'3. Since relay C-3 is energized only incase the receiver R receives the code before the sender I-S transmitsthe code, relay H3 is energized only in case the establishment of theconnection between the apparatus unit AU--3 and its corresponding groupof indicating lamps and relays is initiated in response to the apparatusunit AU"3 changing its position. By closing its contacts 24, relay H3,when energized, completes a locking circuit for itself through contacts26 of the disagreement key DK-3 if it is in its position correspondingto the closed position of the apparatus unit A'U3 and contacts 21 of theindicating relay IR-3 if it is in its position corresponding to theclosed position of the apparatus unit A'U'3. Relay H3, therefore, isoperated before the indicating impulse is transmitted.

If, when the apparatus unit A'U'-3 is opened, it remains in its openposition long enough to allow an indicating impulse corresponding to theopen position of the apparatus unit to be transmitted while the relay H3is energized then indicating relay 1R-3 is moved to its other positionand the locking circuit of the relay H3 is opened so that, as soon asthe supervisory apparatus is reset to normal after the indicatingimpulse is transmitted, the relay H3 becomes deenergized.

When the code sender IS is restored to its normal position after theindicating impulse is transmitted, a circuit is completed through thenormal contacts of bank 1-84 at the dispatchers office for the controlrelay N3. If the relay H3 is energized when the relay N3 becomesenergized, a circuit is completed for relay F which in turn completes aflashing circuit for the white lamp LW3 through an interrupter IR sothat the lamp LW-3 is intermittently lighted at the same time that thered lamp LR3 is continuously lighted. This combination of lighted lampsinforms the dispatcher that the apparatus unit A'U'--3 has opened andreclosed. The dispatcher can then extinguish the flashing white lampLW--3 by operating the disagreement key 7 DKE-3 in the same manner it isoperated in order to extinguish a flashing white lamp in the arrangementdisclosed in Fig. 1.

The operation of the arrangement shown in Fig. 2 is as follows:

When. the selective means is at rest and the 1 apparatus unit A'U'-3 isclosed, the various control devices of the supervisory equipment occupythe positions in which they are shown in. the drawings. At thedispatchers office an energizing circuit for relay N-.3 is completedthrough the normal contact of bank IS4. Acircuit is completed for thered lamp LR- -3 through the contacts 30 of the indicating relay IR-3 sothat this lamp is .continuously lighted and thereby informs thedispatcher that the apparatus unit A'U- 3 at the remote station isclosed. At the remote station the indicating. relay IA-3 is energizedby-a locking circuit which includes contacts ill of the relay IA--3 andthe auxiliary contacts I! of the closed apparatus unit AU'-3.

It will be assumed first that the selector switch SK3 is moved to itsoff-normal position so as to cause the supervisory equipment to operatein a well known manner to establish a connection between the apparatusunit A'U'--3 at the remote station RS and its corresponding indicatingmeans at the clispatchers oflice after which an indicating impulsecorresponding to the position then occupied by the apparatus unit'A'U'-3 is transmitted over the line conductors Ir-l and L-Z to theindicating relay IR-3. If the apparatus unit AU'-3 is still in itsclosed position after the connection is established, the indicatingimpulse is of such a character that the relay Hit-3 remains in theposition in which it is shown so that the lamp LR--3 remainscontinuously lighted. If the apparatus unit AU'3 is in its'open positionwhen the connection is established, the indicating impulse is of such acharacter that the relay IR-3 is moved to its other position, so thatthe red lamp LR-3 is extinguished as the circuit of the green lamp LG--3is completed at the contacts 34 of the relay 13-3. Also a circuit iscompleted for the white lamp LW-3 through the contacts 34 of the relayIR--3, the contacts 36 of the disagreement key DK-3 and the contacts 35of the relay H-3. By moving the disagreement key ,DK--3 to the positionthereof corresponding to the open position of the apparatus unit AU-3,the continuous lighting of the white lamp. LW-3 is discontinued. Theselection may be released at any time by restoring the select key SK-3to its normal position.

It will now be assumed that, While the supervisory equipment is at rest,the apparatus unit A'U'--3 automatically opens so that its contacts I!interrupt the holding circuit for the associated indicating relayI'A'-3. The deenergization of the indicating relay IA-3 then effects 'ina well known manner the establishment of a connection between theapparatus unit A'U'3 and its corresponding group of indicating lamps andrelays at the dispatchers oflice after which an indicating impulsecorresponding to the position of the apparatus unit AU-3 is transmittedover the line conductors Ll and L-Z to the indicating relay IR.3. Sincethe receiver R receives code before the code sender l--S transmits code,the relay H3.is energized in the manner heretofore described before theindicating imdisagreement key DK-3.

pulse is" transmitted to the indicating relay IR-3.

If the apparatus unit AU-3 is'in its open position at the time theindicating impulse is transmitted, this indicating impulse is of such acharacter that} the indicating relay IR-'-3 moves to its other positionso that the contacts 21 andv 30 are opened and the contacts 34 areclosed. The opening of the contacts 21 interrupts the heretoforedescribed locking circuit of the relay H. -3 so that this relay becomesdeenergized as soon as the connection is released after the indicatingimpulse is transmitted. The opening of the contacts 30 of the relayIR--3 extinguishes the red lamp Lit-3, and the closing of the contacts34 completes a circuit for the green lamp LG3 and a circuit for thewhite lamp LW--3 through contacts 35 of relay H-3 when it is in itsdeenergized position and contacts 36 of the The continuous lighting ofthe lamps LG--3 and LW-3 informs the dispatcher that the apparatus unitA'U'--3 has opened and is still in its open position. By moving thedisagreement key DK--3 to its other position, which corresponds to theopen position of the apparatus unit A'U--3, the circuit of the whitelamp LW-3 is opened so that only the green lamp LG-3 remains lighted,

It will now be assumed that, after the apparatus unit A'U'3 opens, it isimmediately reclosed and is in its closed position when the indicatingimpulse is transmitted. Under these conditions, the character of theindicating impulse is such that it does not change the position of theindicating relay IR-3. Consequently, the red lamp LR-3 remains lightedand the locking circuit of the relay H--3 remains completed after thesupervisory apparatus has been restored to its normal condition. Whenthe relay N-3 becomes energized by the finder IF being restored to itsnormal position, theclosing of its contacts 31 completes, throughcontacts 38 of relay 1-1-3, an energizing circuit for relay F. Theclosing of contacts 39 of relay F completes a locking circuit for relayF around the contacts 31 of relay N-3, and the closing of contacts 40 ofrelay F completes a flashing circuit for white lamp LW--3 throughcontacts 4| of relay H-3 and interrupter IR. The continuous lighting ofthe lamp LEI-3 and the flashing of lamp LW-'3 at the same time informsthe dispatcher that the apparatus unit A'U'3 has automatically openedand reclosed and is still in its closed position. By moving thedisagreement key DK-3 to its other position and then back to theposition in which it is shown, the dispatcher can extinguish the lampLW-3 so that only the red lamp LR,3 remains lighted.

While I have, in accordance with the patent sta utes, shown anddescribed my invention as applied to a narficua sustrm and as e bodyingvarious devices diagrammatically indicated, changes and modificationswill be obvious to those skilled in the art, and I therefore aim in'theappended cla ms to cover all such changes and modifications as fallwithin the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a supervisory system in which selective means at two points areadapted to be operated to establish connections respectively between aplurality of movable devices at one of said points and correspondingindicating means at the other point, means responsive to any of saiddevices which device has changed its position and whether at the timesuch an impulse is transmitted that device is in a different positionthan the position from which it moved to initiate theoperation of saidselective means or is in the position from which it moved to initiatethe operation of said selective means.

2. In a supervisory system in which selective means at two points areadapted to be operated to establish connections respectively between aplurality of movable devices at one of said points and correspondingindicating means at the other point, means responsive to any of saiddevices changing its position for initiating the operation of saidselective means so as to establish a connection between the deviceinitiating the operation of said selective means and the correspondingindicating means and for transmitting between said points while saidconnection is established an indicating impulse of a character dependentupon the position then occupied by such device, and means for operatingthe indicating means corresponding to the device which initiated theoperation of said selective means so as to indicate which device haschanged its position and whether or not it has been restored to itsoriginal position at the time'said impulse is transmitted includingmeans dependent upon the character of said impulse for operating theindicating means in one manner when said current impulse is transmittedas a result of said device being in a different position than theposition from which it moved to initiate the operation of said selectivemeans and in a difierent manner when said current impulse is transmittedas a result of said device being in the same position from which itmoved to initiate the operation of said selective means.

3. In a supervisory system in which selective means at two points areadapted to be operated to establish connections respectively between aplurality of movable devices at one of said points and correspondingindicating means at the other point, means responsive to any of saiddevices changing its position for initiating the operation of saidselective means so as to establish a connection between the deviceinitiating the operation of said selective means and the correspondingindicating means and for transmitting be tween said points while saidconnection is established an indicating impulse of a character dependentupon the position then occupied by such device, and means for operatingthe indicating means corresponding to the device which initiated theoperation of said selective means so as to indicate which device haschanged its position and whether or not it has been restored to itsoriginal position at the time said impulse is transmitted includingmeans dependent upon the character of said impulse for operating theindicating means continuously when said current impulse is transmittedas a result of said device being in a difierent position than theposition from which it moved to initiate the operation of said selectivemeans and intermittently when said current impulse is transmitted as aresult of said device being in the same position from which it moved toinitiate the operation of said selective means.

4. In a supervisory system in which selective means at two points areadapted to'be operated to establish connections respectively between aplurality of two-position devices at one of said points andcorresponding normally nonoperating indicating means at the other point,means responsive to any of said devices moving from one of its positionsto another for initiating the operation of said selective means so as toestablish a connection between the device initiating the operation ofsaid selective means and the corresponding indicating means and fortransmitting between said points when such connection is established anindicating impulse of a character dependent upon the position thenoccupied by such device, a disagreement key at said other pointindividual to each device at said one point and having two positionscorresponding respectively to the two positions of the associateddevice, and means for operating the indicating means corresponding tothe device that initiated the operation of said selective means so as toindicate which device has changed its position and whether or not it hasbeen restored to its original position at the time said impulse istransmitted including means dependent upon the character of said currentimpulse and the position of the associated disagreement key foroperating the corresponding indicating means in one manner when saiddevice is in said other position to which it has been moved and in adifferent manner when it has been restored to said one position at thetime said impulse is transmitted.

5. In a supervisory system in which selective means at two points areadapted to be operated to establish connections respectively between aplurality of two-position devices at one of said points andcorresponding indicating means at the other point, means responsive toany of said devices moving from one of its positions to another forinitiating the operation of said selective means so as to establish aconnection between the device initiating the operation of said selectlvemeans and the corresponding indicating means and for transmittingbetween said points when such connection is established an indicatingimpulse of a character dependent upon the position then occupied by suchdevice, a disagreement key at said other point individual to each deviceat said one point and having two positions corresponding respectively tothe two positions of the associated device, and means for operating theindicating means corresponding to the device-that initiated theoperation of said selective means so as to indicate which device haschanged its position and whether or not it has been restored to itsoriginal position at the time said impulse is transmitted includingmeans dependent upon the character of said current impulse and theposition of the associated disagreement key for operating thecorresponding indicating means in one manner when said disagreement keyis in a predetermined position and said impulse is of a predeterminedcharacter and in a difierent manner when said disagreement key is insaid other position and said impulse is of said predetermined character.

6. In a supervisory system in which selective means at two points areadapted to be operated ated position.-

to establish a connection betweena predetermined twoposition deviceat-one' otsaid points and corraponding indicating means at the otherpoint and in which an indicating impulse of current of a characterdependent uponthe position occupied by said device is transmittedbetween said points while said connection is established, meansdependentupon the movement of said device from one position to anotherfor device, a control relay, means dependent upon *9 manuallyontrdlledfmealns and: intermittently in response to thetransmissionoi anindicating impulse or said predetermined character when said.

connection is established as a result of said device changing itsposition.

9. In a'supervisory system in which selective means at two stations areadapted to beeper-ated to establish a connection between an apparatusunit having a normalposition and an oft-normal position at one of saidstations and indicating a means at the other; station comprising anindithe establishment'ot said connection being inlti-' ated by themovement of said device from one position to another ioreilfecting theoperation of said control relay, means dependent upon the characterofsaid impulse and the position of said disagreement key for maintainingsaid relay in its operated condition, and means for operating saidindicating means in one manner when said relay is in its normal positionand in a diilerent manner when said relay is in its opera 7. In asupervisory system in which selective means at two points are adapted tobe operated to establish a connection between a predeter mined movabledevice at one of said points and corresponding indicating means at theother point and in which an indicating impulse of current of a characterdependent upon the position. occupied bysaid device is transmittedbetween said points while said connection is established,

means dependent upon the movement of said deand means at said otherpoint for controlling,

said indicating means in one manner in response to the transmission ofan indicating impulse of a predetermined character when said connectionis established asa result of an operation of said manually controlledmeans and in a different m-annerin'res'ponse to the transmission oi. anindicating impulse of saidpredetermined character when said connectionis established as a result of said device changing its position.

8. In a supervisory system in which selective means at two points areadapted to be operated to establish a connection betweena predeterminedmovable device at one of said points and corresponding indicating meansat the other point. and in which an indicating impulse of current of acharacter dependent upon the position occupied by said deviceistransmittedbetween said points while said connection is established,

means dependent upon the movement of said device'from one position toanother for initiating the operation of said selective means toestablish said connection andthe transmission of said indicatingimpulse, manually controlled means at said other point for initiatingthe operationot said selective means to establish said connection andthe tr nsmission of said indicating impulse, and means at said otherpoint for operating said indicating means continuously in response tothe transmission of an indicating impulse of a predeterminedcharacter'when said connection is established as a. result of an operatin oi said cating 'lamp for each position of said unit and a disagreementlamp and in which an indicating impulse of current of a characterdependent upon the position occupied by said unit is transmitted betweensaid stations while said connection is established, a disagreement keyassociated with said indicating means and having positions correspondingto the positions of said unit, means dependent upon said unit movingfrom either of its positions to the other for initiating the operationof said selective means to establish said connection; and thetransmission of said indicating impulse, and means at said other stationcontrolled by said impulse for selectively operating said indicatinglamps in accordance with the character of said impulse and for operatingsaid disagreement lamp continuously if said unit is in itsofi-normalposition and said disagreement key is in its positioncorresponding to the normal position of said unitwhen said impulse istransmitted and for operating said disagreement lamp intermittently itsaid unit is in its normal position and said disagreement key is in itsposition corresponding to the normal position of said unit when saidimpulse is transmitted as a result of the establishment of saidconnection being initiated by said unit changing its position.

10. In a supervisory system in which selective means at two stations areadapted to be operated to establish a connection between an apparatusunit having a normal position and an oft-normal position at one of saidstations and indicating means at the other station comprising anindicating lamp for each position of said unit and a disagreement keyand in which an indicating impulse of current of a character dependentupon the position occupied by said unit is transmitted between saidstations while said connection is established, a disagreement keyassociated with said indicating means and having positions cortion ofsaid selective means to establish said connection and the transmissionof said indicating impulse, and means at said other station controlledby said impulse for selectively operating said indicating lamps inaccordance with the character of said impulse and means at said otherstationcontrolled by the position of said disagreement key and thecharacter 01 said impulse for lighting said'disagreement lamp indiiferent ways.

11. In a supervisory system in which selective means at two stations areadapted to be operated to establish a connection between an apparatusunit having a normal position and an oil-normal position at one of saidstations and indicating means at the other station comprising anindicating lamp for each position of said unit and a disagreement keyand in which an indicating impulse of currentof a character dependentupon the position occupied by said unit is transmitted e w en saidstations while said connection is established, a disagreement keyassociated with said indicating means and having positions correspondingto the positions of said unit, meansdependent upon said unit moving fromeither of its positions to the other for initiating the operation ofsaid selective means to establish said connection and the transmissionof said indicating impulse, control means at said other station forinitiating the operation of said selective means to establish saidconnection and the transmission of said indicating impulse, a controlrelay at said other station, means for eiiecting the operation of saidcontrol relay only upon the establishment of said connection beinginitiated by the movement of said unit from one position to another,means at said other station controlled by said impulse for selectivelyoperating said indicating lamps in accordance with the character 01 saidimpulse, and means dependent upon the position of said disagreement keyand the condition of said relay for operating said disagreement lamp indiii'erent ways in r ponse to the transmission 01- an impulse of a.predetermined character.

1'2. In a supervisory system in which selective means at two stationsare adapted to be operated to establish a connection between anapparatus unit having a normal position and an oil-normal position atone oi said stations and indicating means at the other stationcomprising an indicating lamp for each position of said unit and adisagreement key and in which an indicating impulse 01 current oi acharacter dependent upon the position occupied by said unit istransmitted between said stations while said connection is established,a disagreement key associated with said indicating means and havingpositions corresponding to the positions of said unit, means dependentupon said unit moving from either 01' its positions to the other forinitiating the operation of said selective means to establish saidconnection and the transmission of said indicating impulse, controlmeans at said other station for initiating the operation of saidselective means to establish said connection and the transmission ofsaid indicating impulse, a control relay at said other station, meansfor eil'ecting the operation of said control relay only upon theestablishment of said connection being initiated by the movement of saidunit from one position to another, means at said other stationcontrolled by said impulse for selectively operating said indicatinglamps in accordance with the character oi! said impulse, and means foroperating said disagreement lamp continuously when said relay is in itsnormal position and said disagreement key is in its positioncorresponding to the normal position of said unit and the indicatingimpulse is of the character corresponding to the normal position of saidunit and for operating said disagreement lamp intermittently when saidrelay is in its operated position and said disagreement key is in itsposition corresponding to the normal position of said unit and theindication impulse is of the character corresponding to the normalposition oi said unit.

13. In a synchronous selector supervisory system in which multipleposition switches at two points are synchronously operated and in whichmeans are provided whereby when said switches are simultaneously inpredetermined positions corresponding to a predetermined movable deviceat one of said points an indicating impulse oi current of a characterdependent upon the position occupied by said device is transmittedbetween said points, means dependent upon the movement oi said devicefor causing said switches to remain in said predetermined positionscorresponding to said device during the synchronous operation of saidswitches for one length of time it said device has not changed itsposition since the previous indicating impulse for said device wastransmitted and for a diflerent length of time it said device haschanged its position since the previous indicating impulse for saiddevice was transmitted, and means at the other of said points dependentupon the character or said impulse and the length of time said switchesremain in sai predetermined positions corresponding to said device forindicating whether said device has been operated so that it is in adifferent position than the position it was in when the previousindicating impulse for said device was transmitted or said device hasbeen operated so that it has been restored to the same position it wasin when the previous indicating impulse for said device was transmitted.

14; In a synchronous selector supervisory system in which multipleposition switches at two points are synchronously operated and in whichmeans are provided whereby when said switches are simultaneously inpredetermined positions corresponding to a predetermined movable deviceat one of said points an indicating impulse of current of a characterdependent upon the position occupied by said device is transmittedbetween said points, means dependent upon the movement of said devicefor causing said switches to remain in said predetermined positionscorresponding to said device-during the synchronous operation of saidswitches for one length of time if said device has not changed itsposition since the previous indicating impulse for said device wastransmitted and for a diflerent length oi time ii. said device haschanged its position since the previous indicating impulse for saiddevice was transmitted, signalling means at the other of said points,and means dependent upon the character of said current impulse and thelength of time said switches remain in said predetermined positionscorresponding to said device for operating said signalling means in onemanner when said current impulse is transmitted as a result of saiddevice being in a different position than the position it was in whenthe previous indicating impulse for said device was transmitted and in adifferent manner when said current impulse is transmitted as a result01' said device being. operated in such a way that it has been restoredto the same position it was in when the previous indicating impulse forsaid device was transmitted.

15. In a synchronous selector supervisory system in which multipleposition switches at two points are synchronously operated and in whichmeans are provided whereby when said switches are simultaneously inpredetermined positions corresponding to a predetermined movable deviceat one of said points an indicating impulse of current of a characterdependent upon the position occupied by said device is transmittedbetween said points, means dependent upon the movement of said devicefor causing said switches to remain in said predetermined positionscorresponding to said device during the synchronous operation of saidswitches for one length of time if said device has not changed itsposition since the previous indicating impulse for said device wastransmitted and for a diflerent length of time if said device haschanged its position since the previous indicating impulse for saiddevice was transmitted, signalling means at the other of said points,and means dependent upon the character of said current impulse and thelength of time said switches remain in said predetermined positionscorresponding to said device for operating said signalling meanscontinuously when said current impulse is transmitted while said deviceis in a different position than the position it was in when the previouscurrent impulses for said device was transmitted and intermittently whensaid current impulse is transmitted as a result of said device beingoperated in such a manner that it has been restored to the' sameposition it was in when the previous current impulse for said device wastransmitted.

16. In a synchronous selector supervisory system in which multipleposition switches at two points are synchronously operated and in whichmeans are provided whereby when said switches are simultaneously inpredetermined positions a current impulse of one polarity is transmittedbetween said points if a predetermined two-position device is in apredetermined one of its positions and a current impulse of the oppositepolarity is transmitted between said points if said device is in itsother position, means for causing said switches during synchronousoperation thereof to remain in said predetermined positions for onelength of time if said device has not changed its position since theprevious indicating impulse for said device was transmitted and for alonger length of time if said device has changed ent position than theposition it was in when the previous current impulse for said device wastransmitted or said device has been operated so that it has beenrestored to the same position it was in when the previous currentimpulse for said device was transmitted.

17. In a synchronous selector supervisory'systerm in which multipleposition switches at two points are synchronously operated and in whichmeans are provided whereby when said switches are simultaneously inpredetermined positions 7 a current impulse of one polarity istransmitted between said points if a predetermined two-position deviceis in a predetermined one of its positions and a current impulse of theopposite polarity is transmitted between said points if said device isin its other position, means for causing said switches duringsynchronous operation thereof to remain in said predetermined positionsfor one length of time if said device has not changed its position sincethe previous inl dicating impulse for said device was transmitted andfor a longer length of time if said device has changed its positionsince the previous inmined polarities and said switches remain in saidpredetermined positions for said longer length of time and for operatingsaid signal intermittently when said indicating impulse is of theotherpolarity and said switches remain in said predetermined positionsfor said longer length of time. a

18. In a synchronous selector supervisory sys-- term in which multipleposition switches at two points are synchronously operated and in whichmeans are provided whereby when said switches are simultaneously inpredetermined positions a current impulse of one polarity is transmittedbetween sad points if a predetermined two-position device is in apredetermined one of its positions and a current impulse of the oppositepolarity is transmitted between said points if said device is in itsother position, means for causing said switches during synchronousoperation thereof to remain in said predetermined positions for onelength of time if said device has not changed its position since theprevious indicating impulse for said device was transmitted,

a non-operating signal at said other point, and means dependent upon thepolarity of said indicating impulse and the length of time said switchesremain in said predetermined positions for operating said signalcontinuously when said indicating impulse is of one of saidpredeterdicating impulse for said device was transmitted and for alonger length of time if said device has changed its position since theprevious indicating impulse for said device was transmitted, anon-operating signal at said other points, means dependent upon thepolarity of said indicating impulse and the length of time said switchesremain in said predetermined positions for operating said signalcontinuously when said indicating impulse is of one ofsaid predeterminedpolarities and said switches remain in said predetermined positions forsaid longer length P of time and for operating said signalintermittently when said indicating impulse is of the other polarity andsaid switches remain in said predetermined positions for said longerlength of time,'and means at said other point for restoring said signalto its non-operating condition after it has been operated.

19. In a synchronous selector supervisory system in which normally idlemultiple position selector switches are provided at two points and whichmeans areprovided whereby when said switches are simultaneously inpredetermined corresponding positions an indicating impulse of currentof a character dependent upon the position occupied by a two-positiondevice at one of said points is transmitted to the other of said twopoints, means for synchronously operating said switches through theircorresponding positions, means for causing said switches to stop in saidpredetermined corresponding positions for a longer time when said devicehas changed its position than when it has not changed its position sincethe last time said switches were in said predetermined correspondingpositions, a signal at the other of said points, a disagreement key atsaid other point having two positions corresponding respectively to thetwo positions of said device, a control relay, means responsive to saidswitches stopping in said predetermined corresponding positions for saidlonger time for effecting the operation of said control relay, meansdependent upon the char acter of the indicating impulse transmittedwhile said switches are in said predetermined corresponding positionsand upon the position of said disagreement key for maintaining saidrelay in its operated condition, and means for operating said signal inone manner when said relay is in its normal condition and in a differentmanner when said relay is in its operated condition.

20. In a synchronous selector supervisory system in which normally idlemultiple position selector switches are provided at two points and inwhich means are provided whereby when said switches are simultaneouslyin-predetermined corresponding positions an indicating impulse ofcurrent of a character dependent upon the position occupied by atwo-position device at one of said points is transmitted to the other ofsaid two points, means for synchronously operating said switches throughtheir corresponding positions, means for causing said switches to stopin said predetermined corresponding positions for a longer time whensaid device has changed its position than when it has not changed itsposition since the'last time said switches were in said predeterminedcorresponding positions, a signal at the other of said points, adisagreement key at said other point having two positions correspondingrespectively to the two positions of said device, a control relay, meansresponsive to said switches stopping in said predetermined correspondingpositions for said longer time for effecting the operation of saidcontrol relay, means dependent upon the character of the indicatingimpulse transmitted while said switches are in said predeterminedcorresponding positions and upon the position of said disagreement keyfor maintaining said relay in its operated condition, and means foroperating said signal in one manner when said relay is in its normalcondition and in a different manner when said relay is in its operatedcondition and said switches are restored to their idle positions.

21. In a synchronous selector supervisory system in which normally idlemultiple position selector switches are provided at two points and inwhich means are provided whereby when said switches are simultaneouslyin predetermined corresponding positions an indicating impulse ofcurrent of a character dependent upon the position occupied by atwo-position device at one of said points is transmitted to the other ofsaid two points, means for synchronously operating said switches throughtheir corresponding positions, means for causing said switches to stopin said predetermined corresponding positions for a longer time whensaid device has changed its position than when it has not changed itsposition since the last time said switches were in said predeterminedcorresponding positions, a signal at the other of said points, adisagreement key having two positions corresponding respectively to thetwo positions of said device, a normally deenergized relay, meansresponsive to said switches stopping in said predetermined correspondingpositions for said longer time for effecting the energization of saidrelay, means dependent upon the character of the indicating impulsetransmitted while said switches are in said predetermined correspondingpositions and upon the position of said disagreement key for completinga locking circuit for said relay, and means controlled by said relay foroperating said signal continuously when the said relay is deenergizedand the position of said disagreement key does not agree with theposition of said device and for operating said signal intermittentlywhen said relay is energized and the position of said disagreement keyagrees with the positionof said device.

22. In combination, a dispatchers ofiice, a remote station, a normallyclosed circuit breaker at said remote station, means for opening saidcircuit breaker, automatic means for reclosing said relay associatedwith said circuit breaker, means responsive to an opening of saidcircuit breaker for deenergizing said relay, indicating'means at saiddispatchers ofilce for indicating the position of said circuit breaker,a selector switch at each station having a normal position and apredetermined off-normal position individual to said circuit breaker,means for transmitting between said stations an indicating impulse of acharacter dependent upon the position of said circuit breaker when bothof said switches are simultaneously in said predetermined oil-normalpositions, means for controlling said indicating means in response tothe character of said indicating impulse and the length of time saidswitches remain in said predetermined ofi-normal positions, meansindependent of the length of said impulses for operating said switchesin synchronism including means for initiating said synchronous operationin response to the deenergization of said relay, means controlled bysaid relay for'stopping said synchronous operation when said switchesare in said predetermined offcircuit breaker, a normally energizedindicating normal positions and said relay is deenergized and forimmediately continuing said synchronous operation when said switches arein said predetermined oil-normal positions and said relay is energized,and means responsive to said switches remaining in said predeterminedoil-normal positions for a predetermined time when said relay isdeenergized for initiating the synchronous operation of said switches.

23. In combination, a dispatchers oflice, a remote station, a normallyclosed circuit breaker at said remote station, means for opening saidcircuit breaker, automatic means for reclosing said circuit breaker, anormally energized indicating relay associated with said circuitbreaker, means responsive to an opening of said circuit breaker fordeenergizing said relay, indicating means at said dispatchers oflice forindicating the position of said circuit breaker, a selector switch ateach station having a normal position and a predetermined off-normalposition individual to said circuit breaker, means for transmittingbetween said stations an indicating impulse of a character dependentupon the position of said circuit breaker when both of said switches aresimultaneously in said predetermined 011- normal positions, means forcontrolling said indicating means in response to the character of saidindicating impulse and the length of time said switches remain in saidpredetermined 01T- normal positions, means independent of the length ofsaid impulses for operating said switches in synchronism including meansfor initiating said synchronous operation in response to thedeenergization of said relay, means controlled by said relay forstopping said synchronous operation when said switches are in saidpredetermined ofi-normal positions and said relay is deenergized and forimmediately continuing said synchronous operation when said switches arein said predetermined off-normal positions and said relay is energized,and means responsive to said switches remaining in said predeterminedoffnormal positions for a predetermined time when said relay isdeenergized for initiating the synchronous operation of said switchesand the energization of said relay,

24. In combination, two stations, an apparatus unit at one of saidstations having a plurality of positions, a normally energized relayassociated with said unit, means responsive to a change in the position01 Said unit for deenergizing said relay, indicating means at the otherof said stations for indicating the position ofsaid unit,

a multiple position switch at each station having a predeterminedposition individual to said unit, means for transmitting between saidstations a current impulse of a character dependent upon the position ofsaid unit when both of said switches are simultaneously in saidpredetermined positions, means independent of the length of saidimpulses and responsive to the deenergization of said relay foroperating said switches to said predetermined positions, meanscontrolled by said relay for effecting the movement of said switches outof said predetermined positions immediately when said relay is energizedand after a predetermined time interval when said relay is deenergized,and means at said other station for controlling the operation of saidsignalling means in response to the character of said imp ilse and thelength of time said switches remain in said predetermined positions.

25. In combination, two stations, an apparatus unit at one of saidstations having a plurality of positions, a normally energized relayassociated with said unit, means responsive to a change in the positionof said unit for deenergizing said relay, indicating means at the otherof said stations for indicating the position of said unit, a multipleposition switch at each station having a predetermined positionindividual to said unit, means for transmitting between said stations acurrent impulse of-a character dependent upon the position of said unitwhen both of said switches are simultaneously in said predeter minedpositions, means for operating said switches to said predeterminedpositions, means responsive to the deenergization of said relay forinitiating the operation of said operating means, manually controlledmeans at said other station for initiating the operation of said'operating means, and means at said other station for controlling saidindicating means inone manner in response to the transmission of animpulse of a predetermined character when said switches are in saidpredetermined positions as a result of an operation of said manuallycontrolled means and in a different manner in response to thetransmission of an impulse of said predetermined character when saidswitches are in said predetermined positions as a result of adeenergization of said relay.

26. In combination, two stations, an, apparatus unit at one of saidstations having a normal position and an oil-normal position, means formoving said unit-from each position to the other, a normally energizedrelay associated with said unit, means responsive to a change in theposition of said unit while said relay is energized for deenergizingsaid relay, indicating means at the other of said stations forindicating the position of saidunit, a multiple position switch at eachstation having a predetermined position individual to said unit, meansfor transmitting between said stations a current impulse of a characterdependent upon the position of said unit when both of said switches aresimultaneously in said predetermined positions, means for operating saidswitches to said predetermined positions, means responsive to thedeenergization of said relay for initiating the operation of saidoperating means, control means at said otherstation for initiating theoperation of said operating means, and means at saidotherstation forcontrolling said indicating means in response to the character of saidimpulse including means for sitions as a result of an operation of saidcontrol means and said unit is in its normal position when said switchesare in said predetermined positions.

2'7. In combination, two stations, an apparatus unit at one of saidstations having a normal position and an ofi-normal position, means formoving said unit from, each position to the other, a normally energifiedrelay associated with said unit, means responsive to a change in theposition of said unit while said relay is energized for deenergizingsaid relay, indicating means at the other of said stations forindicating the position of said unit, a multiple position switch at eachstation having a predetermined position individual to said unit, meansfor transmitting between said stations a current impulse of a characterdep'endentupon the position of said unit when both of said switches aresimultaneously in said predetermined positions, means for operating saidswitches to said predetermined positions, means responsive to thedeenergization of said relay for initiating the operation of saidoperating means, and means at'said other station controlled by saidimpulse for operating said indicating means continuously, if said unitis in its off-normal position when said switches reach saidpredetermined positions in response to the deenergization of said relayand intermittently if said unit is in its normal position when saidswitches reach said predetermined positions in response to thedeenergization of said relay.

28. In combination, two stations, an apparatus unit at one of saidstations having a normal position and an off-normal position, means formoving said unit from eachposition to the other, a normally energizedrelay associated with said unit, means responsive to a change in theposition of said unit while said relay is energized for deenergizingsaid relay, indicating means at the other of said stations forindicating the position of said unit, saidindicating means including anindicating lamp for each position of the unit and a disagreement lamp, adisagreement key associatedwith said indicating means and havingpositions corresponding to the positions of said unit, a multipleposition switch at each station having a predetermined positionindividual to said unit,

means for transmitting between said stations a current impulse of acharacter dependent upon the position of said unit when both of saidswitches are simultaneously in said predetermined positions, means foroperating said switches to said predetermined positions, meansresponsive to the deenergization of said relay for initiating theoperation of said operating means, and means at said other stationcontrolled by said impulse for selectively operating said indicatinglamps in accordance with the character of saidimpulse and for operatingsaid disagreement lamp continuously if said unit is in its off-normalposition and said disagreement key is in its position corresponding tothe normal position of said unit when said switches reach saidpredetermined positions in response to the deenergization of said relayand for operating said disagreement lamp intermittently if said unit isin its normal position and said disagreement key is in its positioncorresponding to the normal position of said unit when said switchesreach ,said predetermined positions in response to the deenergization ofsaid relay.

29. In combination, two stations, an apparatus unit at one of saidstations having a normal position and an oiT-normal position, means formoving said unit from each position to the other, a normally energizedrelay associated with said unit, means responsive to a change in theposition of said unit while said relay is energized for deenergizingsaid relay, indicating means at the other of said stations forindicating the position of said unit, said indicating means including anindicating lamp for each position of the unit, a multiple positionswitch at each station having a predetermined position individual tosaid unit, means for transmitting between said stations 9, currentimpulse of a character dependent upon the position of said unit whenboth of said switches are simultaneously in said predeterminedpositions, means for operating said switches to said predeterminedpositions, means responsive to the deenergization of said relay forinitiating the operation of said operating means, control means at saidother station for initiating the operation of said operating means, aselect key at said other station having a normal position and anofi-normal position arranged when in its normal position to permit theoperation of said operating means to move said switches out of saidpredetermined positions and when in its off-normal position to preventsaid operating means from moving said switches out of said predeterminedpositions, means controlled by said relay for eiTect-ing the movement ofsaid switches out of said predetermined positions immediately when saidrelay is energized and said select key is in its normal position andafter a predetermined longer time interval when said relay isdeenergized and said select key is in its normal position, and means atsaid other station controlled by said impulse for selectively operatingsaid indicating lamps in accordance with the character of said impulseand the length of time said switches remain in said predeterminedpositions. 7

30. In combination, two stations, an apparatus unit at one of saidstations having a normal position and an oiT-normal position, means formoving said unit from each position to the other, a normally energizedrelay associated with said unit, means responsive to a change in theposition of saidunit while said relay is energized for deenergizing saidrelay, indicating means at the other of said stations for indicating theposition of said unit, said indicating means including an indicatinglamp for each position of the unit and a disagreement lamp, adisagreement key associated with said indicating means and havingpositions corresponding to the positions of said unit, a multipleposition switch at each station having a predetermined positionindividual to said unit, means for transmitting between said stations acurrent impulse of a character dependent upon the position of said unitwhen both of said switches are simultaneously in said predeterminedpositions, means for operating said switches to said predeterminedpositions, means responsive to the deenergization of said relay forinitiating the operation of said .operating means, control means at saidother station for initiating the operation of said operating means, aselect key at said other station having a normal position and anoff-normal position arranged when in its normal position to permit theoperation of said operating means to move said switches out of saidpredetermined positions and when in its oif-normal position to r'eventsaid operating 7 means from moving said switches out of said pre- 1determined positions, means controlled by said relay for eifecting themovement of said switches out of said predetermined positionsimmediately when said relay is energized and said select key is in itsnormal position and after a predetermined longer time interval when saidrelay is deenergized and said select key is in its normal position,means at said other station controlled by said impulse for selectivelyoperating said indicating lamps in accordance with the character of saidimpulse, and means at said other station controlled by the positions ofsaid disagreement and select keys and the length of time said switchesremain in said predetermined positions for operating said disagreementlamp in diiferent ways.

31. In combination, two stations, an apparatus unit at one of saidstations having a normal position and an oif-normal position, means formoving said unit from each position to the other, a normally energizedrelay associated with said unit, means responsive to a change in theposition of said unit while said relay is energized for deenergizingsaid relay, indicating means at the other of said stations forindicating the position of said unit, said indicating means including anindicating lamp for each position of the unit and a disagreement lamp, adisagreement key associated with said indicating means and havingpositions corresponding to the positions of said unit, a multipleposition switch at each station having a predetermined positionindividual to said unit, means for transmitting between said stations acurrent impulse of a character dependent upon the position of said unitwhen both of said switches are simultaneously in said predeterminedpositions, means for operating said switches to said predeterminedpositions, means responsive to the deenergization of said relay forinitiating the operation of said operating means, control means at saidother station for initiating the operation of said operating means, aselect key at said other station having a normal position and anoff-normal position arranged when in its normal position to permit theoperation of said operating means to move said switches out of saidpredetermined positions and when in its ofi-normal position to preventsaid operating means from moving said switches out of said predeterminedpositions, means controlled by said relay for eiTecting the movement ofsaid switches out of said predetermined positions immediately when saidrelay is energized and said select key is in its normal position andafter a predetermined longer time interval when said relay isdeenergized and said select key is in its normal position, means at saidother station controlled by said impulse for selectively operating saidindicating lamps in accordance with the character of said impulse, andmeans at said other station controlled by the positions of saiddisagreement and select keys and the length of time said switches remainin said predetermined positions for operating said disagreement lampcontinuously if said select key is in its normal position and said unitis in its oil-normal position and said disagreement key is in itsposition corresponding to the normal position oi said unit when saidimpulse is transmitted and it said select key is in its off-normalposition and the positions of said unit and disagreement key do notagree when said current impulse is transmitted and intermittently ifsaid select key is in its normal position and said unit is in its normalposition and said disagreement key is in its position corresponding tothe normal position of said unit and said switches remain in saidpredetermined positions for said predetermined longer time interval whensaid impulse istransmitted.

32. In combination, two stations, an apparatus unit at one of saidstations having a normal position and an oiT-normal position, means formoving said unit from each position to the other, a normally energizedrelay associated with said unit, means responsive to a change in theposition of said unit while said relay is energized for deenergizingsaid relay, indicating means at the other of said stations forindicating the position of said unit, said indicating means including anindicating lamp for each position of the unit and a disagreement lamp, adisagreement key associated with said indicating means and havingpositions corresponding to the positions of said unit, a multipleposition switch at each station having a predetermined positionindividual to said unit, means for transmitting between said stations acurrent impulse of a character dependent upon the position of said unitwhen both of said switches are simultaneously in said predeterminedpositions, means for operating said switches to said predeterminedpositions, means responsive to the deenergization of said relay forinitiating the operation of said operating means,

control means at said other station for initiating the operation of saidoperating means, a select I key at said other station having a normalposition and an off-normal position arranged when in its normal positionto permit the operation of said operating means to move said switchesout of said predetermined positions and when in its off-normal positionto prevent said operating means from moving said switches out of saidpredetermined positions, means controlled by said relay for effectingthe movement of said switches out of said predetermined positionsimmediately when said relay is energized and said select key is in itsnormal position and after a predetermined longer time interval when saidrelay is deenergized and said select key is in its normal position,means at said other station controlled by said impulse for selectivelyoperating said indicating lamps in accordance with the character of saidimpulse, means at said other station controlled by the positions of saiddisagreement and select keys for operating said disagreement lam-pcontinuously if said select key is in its normal position and said unitis in its oifnormal position and said disagreement key is in itsposition corresponding to the normal position of said unit when saidimpulse is transmitted and if saidselect key is in its off-normalposition and the positions of said unit and disagreement key do notagree when said current impulse is transmitted, and means for operatingsaid disagreement lamp intermittently when said switches are restored totheir idle positions if said select key and units are in their normalpositions and said disagreement key is in its position corresponding tothe normal position of said unit and said switches remain in saidpredetermined positions for said predetermined longer time interval whensaid impulse is transmitted.

CLYDE E. STEWART.

